Centrifugal separator



March 1 1927.

' B- C. CARTER GENTRIFUGAL SEPARATOR 5 Sheets-Sheet Filed Oct 1926 March1, 1927. 1,619,652

B. C. CARTER CENTRI FUGAL SEPARATOR Filed Ogt 23, 1926 s Sheets-Sheet 2March 1 1927.

B. C. CARTER CENTRIFUGAL SEPARATOR Filed Oct, 23, 1926 5 Sheets-Sheet 5'March 1 1927.

B. c. CARTER v CENTRIFUGAL SEPARATOR WNL.

March 1, 1927 1,619,652

B. c. CARTER CENTRIFUGAL SEPARATOR Filed Oct, 23, 1926 5 Sheets-Shec 5V, &

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Patented Mar. 1, 1927.

BENJAMIN CHARLES CARTER, OF LONDON, ENGLAND.

CENTRIFUGAL SEPARATOR.

Application filed October 23,1926, Serial No.

This invention relates to centrifugal separators and consists inimproved constructions of separator especially suitable for insertion inthe oil circulating system of internal combustion engines for freeingthe lubricating oil from fine solid matter; or for freeing fuel oil orother liquids from air or solid impurities; or for freeing air fromsolid and liquid impurities; and also applicable to other purposes.

The separators of the invention desi ned for cleaning liquids comprise abowl filled with the liquid to be cleaned and rotating with it at a highspeed, longitudinal vanes ensuring that the liquid adjacent to the bowlshall be at rest relatively to it, while fluid further removed from thesurface of the bowl can flow slowly but freely along a path parallelwith the axis of rotation and divided from the remainder of the bowl bya perforated wall or equivalent means which will permit the outwardmovement of solid particles of impurity undercentrifugal ac- ,tion butwill tend to prevent; the aggregate or conglomerated deposit of impuritywhich collects within the bowl from returning into and choking the axialpath.- The bowl and the perforated wall or equivalent dividing means aresurfaces of revolution, conveniently right circular cylinders orbarrelshaped, and theiraxis is the axis of revolution. The liquid to becleaned may itself be caused to rotate the bowl and perforated cylinder;for this purpose the liquidmay be propelled into the separator through ahelical passage of decreasing pitch formed in the stationary inlet; inits axial flow within the separator it may be guided parallel to theaxis by longitudinal vanes in the per-, forated cylinder; and it mayleave the separator through another helical path of decreasing pitch andopposite twist formed in the rotating outlet. The effectiveness of theseparator may be increased by dividing the space between the bowl andthe perforated cylinder by transverse partitions or vanes. Where theliguid contains impurities lighter than itsel theremay be a perforatedcylinder bounding the axial liquid path on its'innersurface; and if thelighter impurities are gaseous, as 1n the case of 011 containing air, arelief valve may be provided to permit the escape of the gases fromwithin this inner perforated wall.

143,725, and in Great Britain March 14, 1925.

In separators designed for cleaning air an mperforate bowl is notessential. 1s led through a erforated cylinder the central part of which.is filled by a stream lined body, which may consist of a rotatingportion carrying the cylinder by radial The air vanes and a stationaryportion containing the bearings of the rotating part. Such a separatormay be driven, as above described, by the air to be cleaned beingthrough it along suitable helical pat s, or it umped may be fitted withvanes which will cause its rotation when it it carried through the airat a high speed, as, for instance, upon an aeroplane. Y

Various embodiments of the invention are illustrated diagrammaticallvand byway of centrifugal separator through which the i liquid passes inseveral parallel streams;

Fig. 5 is a vertical section of part of a centrifugal separator fortreating liquid containing air;

Figs. Sand 7 are .longitudinal and transverse sections ofa centrifugalseparator for separating dust and sandfrom air;

Figs. 8 and 9 aresimilar views ofanother form of centrifugal separatorfor separating dust and sand from air; and Fig. 10 is a longitudinalsection of a for of separator which is arranged vertically and in whichcertain shaped.

In the centrifugal separator shown, in

Figs. 1 and 2, an annular drum-is formed with a perforate inner wall '1,an imperferate outer wall or bowl 2,and imperforate annular ends 3, 4connecting said walls. The drum is mounted in antifriction or othersuitable bearings 5, 6 so as to offer little frictional resistance torotation. A running gland 7 on the inlet end of the drum receives astationary hollow inlet boss parts areimade barr'el- I 8 whichcommunicates with the oil supply. The running gland may be formed with ahelical groove 9, of opposite twist to the direction of rotation to aidin preserving a fluid tight running fit between the gland and the inletboss 8. The drum communicat'esjwith the inlet boss 8 through the inletend 10 of the inner wall 1, and with a receivin reservoir orcommunication (not shown through the outlet end 11 of the inner wall 1.The drum may be mounted in a stationary casing 12 of which the inletboss 8 may form part.

The inlet boss 8 is fitted internally with one or more helical vanes 13decreasing in pitch towards the rotary inlet 10, and forming a helicalpassage or passages of decreasing pitch and radial width between acentral stationary cone 14 and the wall of the inlet boss 8. Thesehelical paths terminate adjacent to the rotary inlet end 10 in jets ofsmall cross sectional area. Within the inner wall 1 is a central rod ortube 15 of'the s'amediameter as the base of the cone 14. The annularspace 16 between this rod or tube and the inner wall of the drum forms adirect oil passage-way through the drum, and is divided by approximatelystraight radial vanes 17 extending from end to end. Upon these radialvanes are de-' livered the streams of oil issuing from the jets andadjacent the inlet end 10.

The outlet end 11 of the divided annular space 16 communicates with theflared rotating outlet boss 18, which has one or more internal helicalvanes 19, decreasing in pitch towards the outer end and twisting in theopposite direction to the helical vanes 13 in thestationary inlet boss8. These direct the oil in the reverse direction to that of the rotationof the drum and convert into velocity the remaining pressure to whichthe oil is subjected during rotation of the drum.

The oil issues as jets which by their reaction assist in causing thedrum torotate. The drum is ,thus driven in the manner of the rotor of areaction turbine.

The straight radial vanes 17 may be curved at each end so that the oilis transferred to and from them with minimum shock and loss of energy.-1

Within the bowl 2 are radial vanes 20 dividing it. into sectors, andcompelling the oil to rotate with the bowl. If desired transverse vanes21 may be fitted in the bowl dividing the annular quiescent spacebetween walls 1 and 2 into separating zones.

Oil is delivered under pressure to the stationary inlet boss 8, and" thestationary helical vanes 13 in this boss cause the pressure of the oilto be partially converted into velocity at the exit jets of these vanes.The oil completely fills the annular space 16 and the bowl 2, and duringits passage through the separator the oil travelling axially along theannular space is divided from the oil in the bowl by the perforate innerwall 1, The oil in the bowl is'thus practically motionless relative tothe bowl. The axial velocity of the oil along the divided annular space16 is small, and the.

tendency for turbulence .to "prevent separation of particles is thuskeptlow, whereas the circumferential velocity is high enough to producegreat centrifugal effects. Thus the oil is constrained to (pass slowlythrough the apparatus in a rapi ly rotating divided cylindrical sheet,and the particles of dirt have but a short distance to move radially inorder totraverse the perforate inner wall 1 and become separated fromthe axially The angular velocity of the drum is made i high by makingits efliciency as a turbine as high as possible and by diminishing theviscosity of the liquid. The viscosity of the liquid is made small byworking at as high an oil temperature as possible.

The circumferential velocity of the drum at the region of entry 10 ofthe oil requires to be of the same order as the jet velocity from thestationary entry vanes 13. The latter is limited by the'pressure dropavailable, the viscosity of the oil, and the minimum jet area it ispracticable to adopt. The radius of the stationary inlet vanes istherefore made small to obtain high rates of rotation, Y t

In the arrangement described the important centrifugal action takesplace in the divided annular space 16 and the radius at which a particleis separated is equal to theradius of the stationary; inlet vanes. A

greater centrifuge effect may be obtained by leading the oil out. to, alarger radius during a part of its, travelthrough the apparatus, as bymaking the inner perforate wall 1 and tube 15' barrel-shaped (Fig. 10),the bowl2' andcasing 12' being made spherical in that event; for thesame thickness of annular space,'the axial velocity in the part ofgreater diameter would be less and the time of traversing the apparatusgreater, both of whichfactors tend to give improved separation. Theannular space should be made as thin as possible, and the drum long andof small diameter (rather than short and of large diameter) so that thedistance the particles have to pass radially to effect separation issmall, and the time of traversing the apparatus is large.

Short tubular outward projections, indicated at 1 in Fig. 10, may bearranged at the holes in the perforate wall to prevent return flow fromthe annular bowl back into the annular space within the inner wall withaccompanying return of particles; or, if preferred, the holes in theperforate inner wall may be-counter-sunk from either the outside or theinside, as indicated at 1 or both expedients may be adopted.

The retention of the particles within the annular drum involves somedgree of adhesion to the walls and caking of the deposit. It may beadvantageous and desirable to give the walls a rough surface or to coatthem with grease or other suitable substance to facilitate retention,but'with engine oil the natural gumminess of the de-v posit may sutlice.Cooling of the outside of the drum facilitates gumming and retention ofdeposit. For this purpose the drum may be provided with cooling fins 1(Fig. 10), which may be. exposed to the atmosphere or other coolingmedium. The inner perforate wall tends to check or prevent any flakes ordeposit which may become detached from the wall of the bowl fromre-entering the path along which the oil flows axially, as mightotherwise happen when the apparatus is stopped or is being stziirted,and so obstructing the flow of the o1 For some purposes, for instancefor separating water as well as solid impurities from gasoline, thedevice may be set with its axis vertical (Fig. 10) and the lowermostperforations in the wall 1.. may be omitted. By this meansthe lower endof the annular space between the walls 1f and 2 is wholly cut off fromthe through-flowing stream, and permits the undisturbed accumulation ofany water tha-t may be separated from the gasoline.

Increased separation may be attained by passing the oil in parallel(Fig. 3) or in series (Fig. 4) axially through a system or nest ofconcentric or symmetrical'annular spaces 160 in a separatorhaving innerper forate walls 100 and outer imperforate walls 200, corresponding tothe inner perforate wall 1 and the outer imperforate wall 2 in Fig. 1.In this arrangement alternate im perfora-teand perforate walls. arearranged etween the innermost and outermost walls of the drum, and theseparated matter accumulates on the series of imperfprat'e walls.

or cylinders. This arrangement is directed mainly to extracting matterquickly. The

arrows in Figs. 3 and-4 indicate the direction of flow of the oil fromtheinlet end 10 of the divided annular space 160 to the It will beunderstood that the ends of the drum and the casing may be detachable,as

is shown for the inlet end of the drum and casing in Fig. 1, tofacilitate access thereto for matter.

In treating oil containing air, the air tends to keep near the axis of,rotation under the centrifugal action, and, as shown in Fig. 5 aseparate outlet 22 may be provided through which the air reaches a smallrelief valve 23 loaded to a suitable pressure and located in the centraltube 15 forming the inner wall of the annular space 16. The

relief valve casing runs in a stationary gland 24, which can communicatewith the atmospherethrough a cook 25.

cleaning out. the separated The separator as described maybe con 1strueted small in size and light in weight, and has the importantfeaturethat no mechanical high speed drive, or slipping clutch isinvolved. 1'

, Such a separatormay be incorporated in the sump of an aircraft orother internal combustion engine, which may be provided with twoscavenging pumps, one at each end, each pump being more than capable: ofdealing with the oil in circulation; Oil

cationyand fixed vanes may be used in the pipe line or reservoir.

In the form of construction of cei'itrifugal separator shown in Figs. 6and 7,v the bowl is formed with a perforate inner wall 101 and an outerwall 20l which may be imperforate or perforate as indicated at 37. Thebowl is mountedmon a central spindle 26, supported in antifrictionbearings 27, 28 in an inner housin 29, which is located by means ofradial we s or vanes 30 within an outer housing 31. The outer housing 31is adapted to be applied to the air intake 32 to an internal combustionengine. Helical vanes 33 mounted within the entry of the bowl cause theair drawn in by the engine to rotate the bowl in flowing therethrough. IRadial vanes 34 mounted within the perforate inner wall 101 and whichmay be continuous with the vanes 33, divide the annular space 161between the inner peripheral wall and the central body part,

150 into longitudinal air passage-ways.

Curved vanes 35 which may be continuous with the vanes 34' may belocated within the outlet end of the bowl for straightening out the airstream before it passes into the air intake to the engine to preventturbulence of the air in the intake. The vanes 30 may be curved for thesame purpose. The central body 150 increases the mean radius ofairflowand has a streamline formation.

In addition to or in lieu of using helical vanes within the bowl forimparting a rotational effect to it, the bowl may be furnished withexterior helical vanes 36 or the like,

which are adapted to cause rotation of the bowl b the slip stream orrelative air flow, when the separator is used in an exposed position onan aircraft or other moving vehicle.

In the form shown in Figs. 8 and 9,instead of the spindle 26 beingsecured to the bowl and rotating in hearings in a stationary housing 29as in Fig. 6, it is secured in the stationary housing 29, and the bowlrotates in bearings 38, 39, on the spindle.

Further, instead of the plain perforate inner wall 101 as in Fig. 6, aseries of annular partitions 102 may be employed, and the outer wall maybe pocketed and perforated as at 202. The inner edges of the annularpartitions 102 together with those of the radial vanes 30 form in eflecta perforate inner wall. v

A collector 40, inthe form' of a casing with a radial or outer outlet 41may be attached tothe other stationary housing and perforate area.

extend over part of the bowl including the bowl rotatable at high speedupon itsaxis,

longitudinal vanes u on the inner surface of the wall of said bowl tosaid bowlat opposite ends thereof, and means continuously dividing thefluid path between said inlet and outlet from the remainder of the bowlthroughout theentire length of the bowl said means permitting passage offluid and fine. impur ties along such path while checking return ofconglomerated solid matter to said path.

2. A centrifugal separatorv comprising a bowl rotatable at high speedupon its axis, longitudinal vanes upon the "inner surface of the wall ofsaid'bowl, an inlet and an out- V let to said bowl at opposite endsthereof,

and a continuous perforated wall dividing the fluid path between saidinlet and outlet from the remainder of the bowl throughout the entirelength of the bowl; said wall per.-

This casing serves to gather the dust' or sandwhich has been separated.from the air.

, an inlet and an outlet mitting passage of fluid and fine impuritiesalong such path while checking return of conglomerated solid matter tosaid path.

3. A centrifugal separator'comprising a rotatable bowl, inlet and outletmeans admitting fluid to pass axially through said bowl, and vanes inthe path of said fluid adapted to deflect the same and thereby causerotation of said bowl.

4. A centrifugal separator comprising a rotatable bowl, a fixed inlet inline with the axis of said bowl, helical vanes in said inlet adapted toimpart a whirling motion to fluid passing axially therethrough and ejectit in the form of jets from said inlet, and

vanes in said bowl against which such jets impinge, thereby to causerotation of the bowl.

5. A centrifugal separator comprising a rotatable bowl, a fixed inlet inline with the axis of said bowl, helical vanes in said inlet adapted to"impart a whirling motion to fluid passing axially therethrough and ejectit in the form of jets from said inlet, vanes in said bowl against whichsuch jets impinge so as to cause rotation of the bowl, an axial outletrotating with said bowl, and helical vanes in said outlet extending inthe opposite direction from the first-named vanes to convert thewhirling motion of the fiuid in said bowl into a straight axial flow.

6. A centrifugal separator comprisin a rotatable bowl, longitudinalvanes wit in said bowl, a wall within the bowl having the form of asurface of revolution about the axis of rotation and being perforatedfrom one end substantially to the other means admitting liquid to passaxially through the interior of said perforated wall from end to endthereof and to fill the bowl through the perforations, and meansdisposed axially of said separator for permittingthe escape of gases.

7. A centrifugal separator, comprising a rotary bowl having an inlet atone end and an outlet at the other and embodying connected outer andinner, substantiztlly-eylin drical members disposed in coaxial relation,the inner-member bein perforated from its inlet end approximate y to itsoutlet end;

and means, for admitting fluid at theinlet 'end of saidinner member totravel axially throughthe interior thereof. to the outlet whereby-matterto be separatedcontained in the traveling fluidwill be caused outwardthrough the er-' uid end,

-mately to the other; a stationary cylindrical member extending axi 11ythrough said in- "ner cylindrical. member and roviding an radiallyoutward through the perforations open-ended annular passa e terebetween; as the axial movement of the fluid conand means foradmitting uid at the inlet tinues. and of such lpassage to flow axiallythere- In testimony whereof I have signed my 5 throu h to t e outlet endof the passage, name to this specificationwhere y matter to be separatedcontained in 4 Y Y a the traveling fluid will be caused to pass vBENJAMIN-CHARLES CARTER.

